FBI Joins Search for Missing Montana Teacher

Ryan McVay/Thinkstock(SIDNEY, Mont.) -- Police and now the FBI are racing against the clock to find clues leading to a missing Montana teacher, but will scale back searches in her hometown which began when the 43-year-old mother of two vanished four days ago.

Sherry Arnold disappeared near her Sidney, Mont., home after she went for a jog Saturday morning.

Investigators interviewed a local resident Tuesday who believed he was the last to see Arnold when she jogged past his car at about 6:30 a.m. Saturday.

"I'm not 100 percent sure, but I have a strong feeling it might have been [Arnold]," local resident Lonnie Lyttle told ABC News.

Investigators searching for Arnold are becoming desperate for a break and say they don't have much to go on, but police told ABC News that they will reduce their search on Wednesday, calling off the sizeable search parties that have involved more than 1,000 members of the community in the past few days.

Some are now concerned that the teacher, who has worked in Sidney since 1993, could have been abducted and taken across the nearby Canadian border. Others, including Sidney Police Chief Frank Difonzo, believe she will be found.

"I'm going to be optimistic that we are going to find Sherry. I want us to find Sherry," Difonzo said.

Since she disappeared on Saturday, so many volunteers showed up to help in the search that school buses were needed to move them. Searchers scoured countless square miles of terrain, but they've found only one clue so far: one of her running shoes.

Hundreds of Arnold's friends and neighbors packed a family church to pray overnight, and husband Gary Arnold has said that while the turnout for his wife has brought tears to his eyes, it has felt like an eternity since she went missing Saturday.

"It's horrible," he said. "It's a nightmare, but it's what you go through to get somebody back you love, I suppose."

The couple have five children between them from previous marriages. Gary Arnold has three and she has two.